1. Field of the Invention
This invention relates generally to a door seal choke for a combined microwave and self-cleaning oven and, more particularly, to such a choke which functions both as a thermal insulator during pyrolytic self-cleaning of the oven and to reduce leakage of microwave energy.
2. Description of the Prior Art
In U.S. Pat. No. 3,812,316 to Milburn, there is shown a combined microwave and self-cleaning oven having a metal mesh gasket on the door for sealing against the lip of the oven liner. This gasket seals the opening of the liner not only to prevent the escape of heat, gases, and smoke, but also to prevent the escape of microwave energy.
As set forth in the aforesaid Milburn patent, pyrolytic self-cleaning of the oven can be accomplished by the apparatus and process disclosed in U.S. Pat. No. 3,121,158 to Hurko. In the aforesaid Hurko patent, it is necessary for a mullion heater to be provided around the liner of the oven adjacent the lip of the oven to compensate for heat losses at the door of the oven.
In the construction of microwave ovens, it has become usual to employ choke type microwave energy seals around the door opening. Such chokes typically have a depth of either one-fourth or one-half wavelength and operate either to produce a low impedance to effectively short circuit possible leakage of microwave energy, or to produce a high impedance to effectively block possible microwave energy leakage, depending upon the particular design.